KR102223978B1 - Method of manufacturing a heterogeneous composite - Google Patents

Abstract

According to an aspect of the present invention, a method of manufacturing a heterogeneous composite is provided, the method comprising the following steps:
-Providing a first component and a second component,
ㅇ The first component is porous or can generate pores if it is under hydrostatic pressure,
And the second component comprises a solid with thermoplastic properties,
-Positioning the second component relative to the first component and coupling energy to the second component to cause at least portions of the second component to liquefy and penetrate into the pores of the first component or other structure Causing the first component to be penetrated (interpenetrated) by the second component thereby creating a composite,
-Causing an irreversible transition of at least the second component to create a modified composite
Includes.

Description

Method of manufacturing heterogeneous composites {METHOD OF MANUFACTURING A HETEROGENEOUS COMPOSITE}

The present invention relates in particular to the field of energy generation and conversion, chemical engineering and connection and fixation technology in constituent materials for all kinds of different industries.

For example, for mounting, for electrically conducting and/or heat conducting connection or for other purposes, objects made of porous materical, especially fragile materials (objects) It is often difficult to bond them to other members.

It is an object of the present invention to provide approaches for bonding together connection properties that have hitherto unattainable to objects.

According to an aspect of the present invention, a method of manufacturing a heterogeneous composite is provided, the method comprising the following steps:

-Providing a first component and a second component,

ㅇ The first component is (porous or capable of developing pores when under hydrostatic pressure),

And the second component comprises a solid with thermoplastic properties,

-Positioning the second component relative to the first component and coupling energy to the second component to cause at least portions of the second component to liquefy and penetrate into the pores of the first component or other structure Causing the first component to be penetrated (interpenetrated) by the second component thereby creating a composite,

-Causing an irreversible transition of at least the second component to the modified composite

Includes.

The property "being capable of developing pores under hydrostatic pressure" means that when the first component is subjected to hydrostatic pressure (the pressure exerted by the fluid), the flowable material that causes this pressure is at any location. In the field, it can penetrate, while in other locations it means no or less penetration. Therefore, this property means non-uniformity in terms of mechanical resistance. Examples of materials with such properties are composites of soft and hard materials, or heterogeneous materials whose interfacial adhesion between components is less than the force exerted by the permeating flowable material.

In this specification,'pore (pore, hole)' refers to a property of a material such as pores of a porous material such as a foam (foam) on the one hand, or a composite material such as, for example, a soft and hard material. It refers to a structure that is a kind of non-uniformity (heterogeneity). On the other hand,'pore' also refers to an intentionally created structure, such as a structure manufactured by machining a cavity into a member, or a design-related void.

Thus, in general, for the first components, non-uniformity is required with respect to the structure (porosity, which includes the fabricated structure and geometric design) or with respect to the material composition.

Substances with thermoplastic properties are converted from solid to liquid above the critical temperature range, for example by melting, and reconverted to solid materials below the critical temperature range by crystallization (especially C, P, S Or Si chain based), whereby the viscosity of the solid phase is several orders of magnitude greater (at least 3 digits) than the viscosity of the liquid phase. Materials with thermoplastic properties are not limited to macromolecules (polymers) in the narrow sense of the word, and include, for example, waxes. Materials with thermoplastic properties may exhibit viscoelastic properties, but need not.

Thermoplastics generally include polymeric components that are crosslinked with covalent bonds or that do not crosslink in such a way that upon heating above a critical temperature the crosslinking bonds reversibly open.

The irreversible transition causes the chemical properties of the corresponding material-in particular the matrix material of the second component, to change essentially at the molecular level. In other words, the irreversible transition may include a chemical transition.

In embodiments, the irreversible transition of at least the second component is caused by energy input to the composite. This may include heat treatment, for example. For example, the irreversible transition can be caused by heating the composite material after penetration, for example to a temperature of 350° C. or higher, 500° C. or higher, or even 600° C. or higher.

Additionally or alternatively, the energy input to the composite may include irradiation.

If the second component or its polymerized component (such as a polymeric matrix material belonging to the second component) is based on carbon chains, the irreversible transition in the first group (oxidizing atmosphere) is at least to some extent decomposition of these components ( Pyrolysis and/or oxidation;'burning'). The second group (lack/lack of oxygen; reducing atmosphere), irreversible transition may include carbonization or graphitization of constituents. In both groups, the irreversible transition may additionally or alternatively comprise a transition of carbon atoms or molecules containing carbon to another component of the second component or in particular of the first component to an atomic solution. Then, depending on the materials of the constituents, additional treatment, such as a firing step, in which the powdery phase is optionally converted to a solid phase by a sintering process, can be carried out.

When the second component or its polymerized component (such as a polymeric matrix material belonging to the second component) is a polymerized silicate, the transition may include a transition to a mineral or polymerized silicon oxide.

The polymerization component may additionally or alternatively also comprise polyphosphates, polysulfides, or inorganic polymers.

In one group of embodiments, the irreversible transition causes the penetrating material of the second member to lose its thermoplastic properties.

In addition or alternatively to the energy input, the irreversible transition can be caused by changes in other deliberate environmental conditions, such as exposure to a substance or the like, for example.

Additionally or alternatively, the energy that causes the irreversible transition can be released by chemical reactions occurring within or between the components themselves.

Additionally or as another alternative, the irreversible transition is a chemical reaction between the components, and the chemical reaction is made possible by intimate contact between the components caused by the permeation step.

According to a first possibility, the irreversible transition of the second component to the modified composite material occurs after penetration of the first component by the second component and after re-reconstitution of the second component.

According to a second possibility, for example, if the irreversible transition is a reaction between components, or at least one of the first and second components is highly reactive and is caused by conditions occurring during the infiltration step. When caused, penetration and metastasis occur at least partially simultaneously. This results in the release of energy of the above-described kind leading to an irreversible transition.

According to one option, by the same process causing an irreversible transition of the second component, an irreversible transition of the first component is also caused.

A first embodiment of this configuration with an irreversible transition of both components is the case where the first component is a green body, and the irreversible transition includes the step of firing the shaped body.

The second embodiment of this configuration is a configuration in which the first component and the second component undergo a chemical reaction, and as a result, they are chemically bonded to each other. As an example, the first component may include a cellulose structure having cellulose fibers, the second component may include polyacrylonitrile, and the product (modified composite) after heat treatment is a carbon fiber composite material. composite) (CFC).

The invention according to these aspects allows penetration of the body of the first component by methods and/or materials that were not possible so far.

In one group of embodiments, the second component having thermoplastic properties comprises a filler made of a different material, for example a metal, in addition to the matrix of a thermoplastic polymer-based material. At this time, the irreversible transition may mainly be a transition of the thermoplastic matrix, for example, a transition from a low (electrical/thermal) conduction state to a high conduction state.

For the penetration of the first component by the thermoplastic second component, according to the prior art, mainly injection molding techniques have been used. However, in standard injection molding methods, the injected melt is at a higher temperature than the mold and the first component, and the injected melt begins to solidify inward from the interface to the mold/first component. Thus, the melt will have a tendency to freeze in contact with the mold or the surface of the first component that may have to penetrate. More generally, the flowability will be lower at the interface to the surface of the mold/first component than at the inside of the melt. This makes penetration of very small structures and/or structures with high aspect ratio difficult. To deal with this problem, it may be necessary to carry out the injection molding method under a very high melt pressure with a very hot mold. This is, firstly, not economical, and secondly, not feasible for all molds, especially if the mold does not have a standard mold material and is a different work item of material and size that is dependent on a specific purpose. Also, for this the first component must be inserted into the mold to enable processing, while in many embodiments of the invention this is not necessary, because the first component itself is responsible for the part of the mold cavity to be filled. Because.

Other prior art approaches include Chemical Vapor Deposition (CVD; CVD is confined to the surface and not suitable for filling structures with high aspect ratios), and penetration by slurry of powder (with very limited applications). Includes.

Both methods are limited by the complexity of the processes, e.g. CVD requires long-lasting high deposition processes under vacuum conditions, slurry penetration results in very large shrinkage or volumetric transformation from liquid to solid by drying. It is limited by the complexity of the processes such as losses.

The invention according to these aspects suggests, in contrast, that the second component is provided and arranged for the first component as a solid. At this time, both pressure and temperature rise can occur very locally at the interface of the first component, making penetration of the structure by the second component much easier. In general, if the liquefaction of the initially solid second component occurs at or near the interface to the first component, the flowability will be particularly close to this interface.

The invention can be used, for example, for the following applications or combinations thereof:

-Mechanical reinforcement of a porous material and/or a reinforced mechanical connection between such a porous material and a joining element fixed therein.

-Enabling contact of porous materials (not electrically conductive), for example in order to conduct charge to and from materials in catalysts, fuel cells, etc.; This includes, as previously discussed, selective contact by electrical contacts that are electrically isolated from each other;

-For example, if the porous material is a central member such as a solar collector, heat exchanger, cooling member, etc., it is possible to contact the porous material for the conduction of heat to and from the material.

-The formation of a deep zone (compared to the prior art) with the nature of the interphase between the first component and the second component.

In particular if the irreversible transition is caused in a process where the components are at least locally elevated temperature (e.g. sintering temperature), there is only a deep (e.g. 1-10 mm deep) penetration zone, as well as within said zone. , During the process, there will be an elevated degree of diffusivity of the atoms or molecules of the first and/or second component, which leads to a correspondingly elevated exchange at the atomic/molecular level. Thus, interphase effects such as precipitation and/or accumulation of intermetallic compounds (intermetallic phase) or elements near the interface at the boundary between components occur through the permeation zone, and conventional It does not occur only in thin interfacial layers of several atomic layers, as in technology. In embodiments where the pore-to-pore distance is similar to the range of the diffusion process at the heat treatment temperature (of the treatment where the irreversible transition is caused), the infiltrating (penetrating) zone may be formed as an interdiffusion zone with essentially homogeneous properties, and , The depth of this area approximately corresponds to the depth of penetration. Thus, effects due to the mesophase properties or precipitation such as hardening, improved ductility, etc. will be much more depth-effective than in the prior art, which relies solely on surface effects.

The (porous, first component) materials of the first class of interest to which the method is applied, ie powder based foams, for example ceramic foams, are sintered.

Therein, in the first subclass, penetration can optionally already occur in the shaped body (before sintering).

-In this case, the second component may itself have a ceramic material that is thermoplastic prior to sintering/firing. These materials exist for example in the case of ceramic fillers embedded in a matrix of thermoplastic polymer (polymer) known for parts manufactured by CIM (ceramic powder injection molding).

Alternatively, the second component may be a material that exhibits metallic properties after sintering/firing. For example, the second component can include metallic fillers within a matrix of a thermoplastic polymer. Thereby, a close bonding between the ceramic component and the metallic component is achieved.

Applications may include joints designed to receive mechanical loads such as bearings.

Other applications include joints with specific thermal properties, for example thermally insulating (the second component itself becomes a ceramic) or thermally conducting (e.g. when the second component is metallic). I can.

Even further applications may include electrical junctions for conducting charge to/from the ceramic body surface.

The ceramic foam or green body can be solid and have some mechanical stability. However, the stability is not sufficient for the bushing to be fixed therein by conventional methods (press fit, screwing, etc.). Also, injection molding is not an option if ceramic foams or molded bodies are present. In contrast, the approach according to aspects of the invention offers the possibility of fastening the bushing to a ceramic foam or a corresponding shaped body. Different uses of the bushing (with or without a collar at its proximal end) or its bonding to additional parts are possible. All the possibilities that exist for the bushing are available.

Additional advantages of this first subclass include improved mass exchange at the interface due to the remaining mobility within the shaped body, resulting in an extended and more tight bond. The approach according to the invention in the shaped body as a first component leads to interfacial diffusion exchange during the firing or post heat treatment process.

Also, the irreversible transition can lead to contraction of the second component. If the first component is a molded body, sintering/firing can also lead to shrinkage of the first component. Thereby, the shrinkage effect can be compensated for by an appropriate selection of material parameters and geometries. In addition, this makes it possible to intentionally introduce the required stress distribution in the modified resulting composite. The shrinkage of the second component can be controlled by controlling the filling level and properties of the filler in the second component; Similarly, the shrinkage of the first component can be controlled by density (eg when the first component is sintered during an irreversible transition), fill level or other property. For example, it is possible to intentionally cause a compressive stress to stabilize the composite.

For example, if the second component is a ceramic (powder embedded in a polymer matrix), it is itself used to represent any desired shrinkage behavior with respect to the shrinkage behavior of the compact, which can be tuned by the compact powder density and composition. The powder density of the two components can be adjusted for the second component. From a general rule of thumb, components with high powder density will contain less pronounced shrinkage.

In the second subclass, the first component comprises a fired ceramic. In this second subgroup, the first component will not undergo significant transition after penetration. Also in this second subgroup the second component may be selected to include ceramic, metallic or other properties, and the applications include the same group of applications as for the first subclass. Thus, the material of the second component may again be a thermoplastic ceramic material before sintering/firing, in which case there will be a second firing step. There are also other options, for example thermoplastics with metallic fillers, in which the thermoplastic matrix material is carbonized after penetration.

The first component material of the second class is, for example, graphite or carbon/carbon composites such as graphite foams. The above considerations for the first class (second subclass) regarding possible second component materials and their applications also apply to graphite. In particular, the approach according to the invention makes it possible to contact the porous graphite thermally, electrically or mechanically. The material of the second component (or at least its thermoplastic matrix) can be carbonized and, if desired, graphitized after application by a process according to aspects of the invention. A particularly interesting application of this is for the central body of solar collectors.

Among known solar energy plants, there are plants comprising mirrors or other light-directors that direct incident sunlight to a central body, from which heat is conducted and to generate electricity, for example in a thermal power station. Is used. In this case, for example, when the sun is suddenly shaded by clouds, the central body can be subjected to enormous and rapid temperature changes. Therefore, the material of the central body must have the following capabilities;

-Absorbs heat very well;

-Conducts heat very well;

-High heat resistance and temperature shock resistance;

-Having small thermal expansion; And

-Mounting is possible by means to conduct heat very well.

All of these conditions except the last one are satisfied by graphite, in particular graphite foam.

The present invention now relates to a method of mounting a member (i.e. a second component thermoplastic material or other member that is brought from a solid state to a liquid state, penetrates the pores of the graphite foam in the liquid state and is then reconstituted to be fixed to the graphite foam). By providing an approach that also meets the last condition. In addition, the mounting member can then be modified, for example by carbonization and graphitization, to itself become like graphite (this can follow a known carbonization/graphitization process).

Accordingly, the present invention according to another aspect relates to a solar or other radiant energy collection facility, the facility comprising a central body and at least one solar redirector, wherein the solar redirector focuses incident sunlight on the central body. Configured to be directed upwards, wherein the central body comprises porous graphite and also comprises a member fixed therein, which member (this is in some cases at least one heat exchange tube having a thermal interfacial bond to the central body or Other members) are fixed to the porous graphite by a method comprising the following steps:

Providing an opening in the central body, providing a solid at least partially thermoplastic member, applying energy to the at least partially thermoplastic member, thus causing at least partially liquefying the thermoplastic member, the thermoplastic member Causing the liquefied portions of the to penetrate into the pores of the central body near the opening, causing these portions to re-solidify, and causing at least an irreversible transition of the liquefied, re-resolidated portions of the thermoplastic member. In particular, this irreversible transition may be carbonization.

It is possible to provide a central body with a second component that has not yet been carbonized, and it is possible to ensure carbonization only upon irradiation by solar radiation.

A particular material, particularly of interest both, such as the material of the first component and of the second component, is silicon carbide. In particular, SiC is a material of interest for application in the thermal solar power industry because of its high heat resistance.

The first component materials of the third class are metal, ie metallic foam.

In this case, the second component material may include, for example, a metallic filler. After the irreversible transition, the bonding caused by the process according to the invention is, for example, a metal-to-metal transition. The penetration zone between the first component and the second component can be transformed to include the following properties of interest:

In a group of embodiments, the permeation zone can be converted to a eutectic composition or to exhibit properties of the intermetallic phase (by selecting the material composition and, for example, the treatment temperature at which the irreversible transition is caused).

-The polymer matrix of the second component will lead to an abundance of elemental nitrogen, depending on the available elemental carbon and the selected polymer. Matrix materials containing phosphorus or other reactive elements that form the constituents of the process induced precipitate may also be used. This can be used to deliberately initiate heat induced diffusion leading to curing of the first component in or adjacent to the penetration zone. In contrast to prior art surface hardening techniques, it is not limited to a zone of several nanometers, but extends through the entire depth of the penetration zone.

Similarly, for example, for the filler of the semiconducting first component or the second component, a depth-effective doping can be applied to the selected dopant material, for example (N, P, C, etc.). By providing a thermoplastic polymer matrix. Thereby, a large-surface P-N-transition becomes possible to achieve.

Similarly, solid state effects caused by different material pairs, such as local changes in electrochemical potential (sensor, charge generation, or charge separation-capacitor, with large area active interface, etc.) can be achieved.

The first component material of the fourth class is a heterogeneous material. In an embodiment, the first component material may be a two-dimensional or three-dimensional structure, such as, for example, a textile structure of fibers, in particular ceramic fibers, carbon fibers and/or metallic fibers. These fabric structures can constitute a pre-made product to later provide a matrix such as a polymer matrix by resin penetration, or a metallic matrix by melt penetration. According to the approach according to the invention this preform can be provided with additional elements (of the second component), for example bushings and electrical contacts, thermal contacts and the like. The matrix is provided to the first component only after penetration and in some cases also after the irreversible transition.

As an application, referring to different kinds of first component materials, the second component is between a porous material and a non-porous material for mechanical mounting, heat transfer and/or electrical transfer, which is both smooth and at the same time robust. Mounting and/or bonding means, such as, for example, metallic bushings/tubes or SiC or graphite bushings to provide bonding may be included and/or may be provided and/or may be bonded to the mounting and/or bonding means.

Another application of the method according to an aspect of the invention is the provision of a feed through which is instantly sealed against the interior of the porous material.

Looking at the second component material in general, the material known from Powder Injection Molding (PIM) is a material of the class of interest, as well as the availability of the second component for embodiments of the method and apparatus according to the invention. Make up the material.

The first sub-class of material known from PIM is a material known from Ceramic Injection Molding (CIM), including micro-ceramic injection molding.

In this case, the matrix materials (called'binders' in CIM) are different materials including waxes, e.g. polyolefin wax, polyoxymethylene (POM), polyethylene, polypropylene, polyamide, and polyvinyl alcohol. It is a kind of thermoplastic material. The ceramic powder is, for example _{, any desired ceramic, such as conventional ZrO 2} , Al ₂ O ₃ , TiO _2, and mixtures thereof with each other and/or mixtures with other oxides (yttrium oxide, hafnium oxide, etc.), as well as It may be a powder of other ceramics known from various applications. The average particle size may range between 0.1 μm and 5 μm, in particular between about 0.5 μm-2 μm. Teaching materials (feedstock) for CIM can be found in W. Bauer et al.: "Advanced Micro and Nanosystems", Vol. 3 (Microengineering of Metals and Ceramics), Chapter 12, pages 325-356, especially pages 328-333 and 345-347.

The second sub-class of material known from PIM is a material known from Metal Injection Molding as discussed further below.

A particularly suitable material for parts of the thermoplastic matrix material is polyacrylonitrile. Another suitable material includes poly-(aromatic hydrocarbon) polymers, including polymers of polycyclic aromatic hydrocarbons. Examples are cellulose/saccharide based thermoplastic polymers. For teaching on the criteria for polymer carbonization, see Y.N. Sanazov and A.V. Gribanov, Russian Journal of Applied Chemistry, 2009, Vol. 82, pp. 473-482 and references cited therein.

In all aspects according to the first possibility, the energy is provided in the form of mechanical vibration (or, synonymously with oscillation) The energy of the mechanical vibration is in particular the incoupling face of the second component. ) Can be coupled into the second component from a sonotrode having an outcoupling face in contact with the second component, the material of the second component having a dominant energy absorption due to friction due to vibration energy. It can be transferred to the interface with the first component, whereby the temperature of the second component is particularly high at the interface with the first component, and liquefaction begins from this interface.

According to another possibility, the energy is provided in the form of radiant energy, for example laser radiation. A method of causing the required localized heating for the required liquefaction includes coupling electromagnetic radiation to one of the device parts to be fixed and designing one of the device parts to be able to absorb the electromagnetic radiation. In particular, the second component may be essentially transparent to radiation, while for example the first component is not. At that time, the radiation will be mainly absorbed by the first component at the interface to the second component, whereby the first and second components have the effect of being very locally heated where the penetration occurs, and this absorption is It preferably takes place in or in the immediate vicinity of the fastening material to be liquefied. Preferably electromagnetic radiation in the visible or infrared frequency domain is used, and the preferred source of radiation is the corresponding laser.

Other energy sources such as for example mechanical rotation, or resistance heating, and the like are not excluded.

Mechanical vibrations or oscillations suitable for devices and methods according to embodiments of the invention comprising liquefaction of the polymer by frictional heat generated through mechanical vibrations are preferably between 2 and 200 kHz (much more preferably 10 to Between 100 kHz, or between 20 and 40 kHz) and a vibration energy of 0.2 to 20 W per square millimeter of the active surface. The vibrating member (tool, for example a sonotrode) is for example designed so that its contact surface vibrates primarily in the direction of the member axis (longitudinal vibration) with an amplitude of 1 to 100 μm, preferably about 10 to 30 μm. . Rotational or radial vibrations are also possible.

For certain embodiments of the devices, it is also possible to use, instead of mechanical vibration, a rotational motion to generate the mentioned frictional heat necessary for the liquefaction of the stationary material. This rotational motion preferably has a speed in the range of 10,000 to 100,000 rpm.

The liquefiable thermoplastic materials described herein may be liquefiable, for example by mechanical vibration, in particular by comprising at least one thermoplastic component, which when heated, in particular when heated through friction, i.e. in contact with each other. And when disposed on one of a pair of surfaces (contact surfaces) that oscillate or rotate with respect to each other, it becomes liquid or flowable, and the vibration frequency is between 2 kHz and 200 kHz, preferably 20 It is between kHz and 40 kHz and the amplitude is between 1 μm and 100 μm, preferably between about 10 μm and 30 μm. These vibrations are generated for example by means of ultrasonic devices such as those known for example ultrasonic welding. For applications where mechanical vibration energy is to be transferred within the second component over a significant distance, the second component material may have a modulus of elasticity of at least 0.5 GPa, preferably at least 1 GPa. (The material property values referred to herein relate to room temperature (23° C.) unless temperature is mentioned or otherwise defined herein).

However, for some applications, the thermoplastic material can also be significantly softer. In particular, when liquefaction occurs directly at the interface between the tool and the second component, the mechanical energy need not be transferred through the second component itself. Thus, during and after the process (thus also generally at the temperature at which it is used, for example at room temperature) it can even be similarly soft to the point of becoming waxy. In other words, the advantage of a modulus of elasticity of at least 0.5 GPa does not apply in these systems and is at least not significant.

For applications where liquefaction occurring directly at the interface to the vacuum tool is optional, an elastomer for the second component thermoplastic may be used.

Specific embodiments of the matrix materials are: polyetherketone (PEEK), polyetherimide, polyamide 12, polyamide 11, polyamide 6, polyamide 66, polycarbonate, polymethylmethacrylate, polyoxymethylene , Or polycarbonate urethane. A material of interest to be carbonizable for graphite is polyacrylonitrile.

Still other embodiments, particularly including ceramic fillers, are the above-mentioned materials known to be suitable for (micro-) Ceramic Injection Molding (CIM).

Still other embodiments are thermoplastics known to be suitable for carbonization/graphitization, for example as mentioned above.

Another category of materials are those known to be suitable for micro-injection-molding (MIM). Teaching materials for MIM can be found in R. Ruprecht et al.: "Advanced Micro and Nanosystems", Vol. 3 (Microengineering of Metals and Ceramics), Chapter 10, pages 253-287, especially pages 271-272.

Another category of materials are those that have metallic fillers and are known to be suitable for (micro-) Metal Injection Molding (MIM). They are made of thermoplastic matrices, such as polyoxymethylene (POM), polyethylene (PE), polypropylene (PP), polyamide (PA), poly(vinyl alcohol) (PVA) or modified versions of these components. Includes. The filler may be a powder of a metal such as stainless steel, iron, an alloy (pre-alloyed or an external mixture with alloy powder) or other suitable material. The particle size is often in the range between 0.5 μm and for example 20 μm, in particular between 1 μm and 10 μm. Teaching materials (feedstock) for MIM can be found in V. Piotter et al.: "Advanced Micro and Nanosystems", Vol. 3 (Microengineering of Metals and Ceramics), Chapter 11, pages 289-324, especially pages 293-301.

A material particularly suitable as a matrix material to be filled by a filler (eg ceramic or metallic) is a polyolefin.

In the case of a thermoplastic matrix material, even if the filler material comprises up to 80% or 85% (vol.%) of the material of the second component having thermoplastic properties, processes according to aspects of the invention can be used, which It also makes the processes suitable for materials that are not injection-molded. Despite the high degree of filling, the material can continue to flow well, because of favorable flow conditions, e.g. short flow distance, low flow aspect ratio, low flow velocities, as well as missing flow obstructions, missing high aspect ratio channels, Or because of missing flowability requirements in the extruder, such as in injection molding. In injection molding, further obstacles consist of gates or the like, for example.

When a liquefiable material is liquefied not by vibrational energy but by electromagnetic radiation, for example a specific frequency range such as calcium phosphate, calcium carbonate, sodium phosphate, titanium oxide, mica, saturated fatty acids, polysaccharides, glucose or mixtures thereof. It may locally contain compounds (particulate or molecular) capable of absorbing such radiation (especially in the visible or infrared frequency range).

The material of the tool (eg sonotrode) and/or the material of the auxiliary member may be any material that does not melt at the melting temperature of the liquefiable material. In particular, the tool and/or auxiliary member may be composed of a metal such as a titanium alloy, for example. The preferred material is titanium grade 5. These materials, in addition to those generally suitable for fixable devices, have relatively low heat conduction. Because of this poor heat conduction, the melting zones occurring in the liquefiable material and at the interface to the directing structure heat up quickly without heating the surroundings to too high a temperature. Alternative materials for tools and/or auxiliary members are other titanium alloys, stainless steels, low damping (attenuation), temperature and wear resistance other metals such as Fe, Ni or Co-based alloys, zirconium oxide or aluminum oxide, silicon nitride. Ceramics such as lide or silicon carbide, or hard plastics such as PEEK. In order to optimize the abrasion resistance to the damping behavior and toughness, the parts of the tool that interact directly with the abrasive, ie highly ceramic or metal powder filled thermoplastics, can be made of ceramic. In some cases it is not necessary, but in combination with it, the elongated sonotrode shaft can be made of a minimally damped metal alloy or an amorphous metal (metal glass).

The present invention has the effect of providing approaches for bonding together bonding properties that have hitherto been unattainable to objects.

In the following, a method for carrying out the present invention and implementations is described with reference to the drawings. The drawings are generally schematic. In the drawings, the same reference numerals refer to the same or similar members. The drawings show:
1a to 1d show the steps of a process for manufacturing a heterogeneous composite;
-Figure 2 shows a second component;
Figures 3 to 7 show alternative configurations which cause penetration of the first component by the material of the second component;
Figures 8a to 9b show schematics showing transitions between adjacent components according to the prior art and between adjacent components according to the approach according to the invention;
10 shows a solar energy platform; And
11 shows a flow chart.

1 shows a first component 1 of a material having pores or of a material in which pores can be formed under hydrostatic pressure. The second component 2 is provided in the illustrated embodiment as a pin-shaped thermoplastic member. As shown in FIG. 1B, for processing, a second component is disposed relative to the first component. In the configuration shown, the first component includes a hole into which the second component is inserted.

Then, by means of a suitable tool 3, the energy is combined into the second component. The tool 3 can be, for example, a sonotrode. By the impact of energy, the thermoplastic material is melted at least locally where it is in contact with the first component, so that under pressure acting from the tool pressed in the direction shown by the double arrow in FIG. Penetrate the first component material. Fig. 1c very schematically shows the arrangement after the energy impact has ceased and after the thermoplastic material has been reconstituted.

The process parameters of the step leading to the penetration of the first component by the material of the second component can be selected, for example, similar to the process described in WO 98/42988 or the process described in WO 00/79137.

The penetration of the first component by the thermoplastic material leads to a mixing zone 11 comprising a heterogeneous mixture of the first component material and the thermoplastic material. The depth of the mixing zone 11 depends on the properties of the first component and the pressure applied during the infiltration process. Typically, the depth d of the mixing zone will have the order of 1 mm-10 mm-because for open porous first component materials with large pores this can also be larger.

After resolidification of the thermoplastic material, the composite material as shown in Fig. 1C is subjected to a treatment that causes an irreversible transition. For example, the process may include heating to a high temperature, such as a firing process. Thereby, the thermoplastic material can be caused to undergo a transition, for example by burning/pyrolysis or burning completely. This can cause a contraction of the second component. At the same time, optionally also the first component can make an irreversible transition. In an embodiment, the first component is a green body that is initially fired in the process. In another embodiment, the first component may comprise a foam (foam) of a meltable material such as a metallic foam (foam). Also, the first component may undergo a shrinking process. If the material parameters of the first and second components are chosen such that the shrinkage of the second component is overcompensated by the shrinkage of the first component, this can cause a compressive stress in the composite and thus mechanically stabilize the composite. I can make it. More generally, the materials and geometries can be selected so that the same or different shrinkage can result in the required stress distribution and final dimensions.

In Figure 1D, the resulting composite is shown after an irreversible transition. It is assumed that the first component 1 has undergone a transition-for example sintering-causing it to shrink. Arrows indicate compressive stress on the composite.

The second component 2 is shown as having metallic properties after transition. This can be caused, for example, by the second component having a metallic filler embedded in the polymer matrix, where the polymer matrix is burned/carbonized in an irreversible transition process.

Thus, the illustrated embodiment results in, for example, a bonding between the ceramic first component 1 and the ultimately metallic second component, the bonding having a penetration depth of between about 1 mm and about 10 mm. It entails penetration of the first component by the second component with the zone 11.

As schematically shown in Fig. 2, it is not necessary that the second component 2 is composed of a material having thermoplastic properties at least prior to the irreversible transition. Rather, the second component may be a hybrid (hybrid). In Fig. 2, the second components are, for example, metallic or ceramic or plastic (but liquefiable at a temperature higher than the melting temperature of a solid having non-thermoplastic or thermoplastic properties) and a core 21 and a coating 22 and a thermoplastic. It is shown to comprise a core 2 made of a coating of a material having properties. To be suitable for the process, the second component requires a thermoplastic material that, when liquefied, comes into contact with or is capable of contact with the first component.

Figures 3 and 4 both show variants of the penetration step with mechanical vibration energy. In both variants, in contrast to the embodiment taught above, the second component is not directly pressed against the first component in the process, and the pressure is applied to the tool 3 (sonotrode) and the counter member (counter). element) on the second component. Thereby, the process is also applicable in situations where the first component is not suitable for receiving large mechanical loads.

The tool 3 of FIG. 3 is shown to have a shaft portion 3. 1 and a foot portion 3.2. The shaft portion extends through the second component, and the foot (its distal facing outcoupling face) is in contact with the distal end of the second component (2), so that the vibration is brought into the second component at its rear end. Can be combined from

In the variant of FIG. 3, the second component 2, due to its construction-it comprises a number of members which are expandable and movable along conical/oblique surfaces with respect to the axis 31-tool 3 The compression of the second component between the opposing member 4 causes the second component to expand laterally and press against the side walls of the opening 1.1 of the first component. Thereby, when vibrations are coupled into the arrangement, friction between the first and second components may cause or at least support liquefaction of the thermoplastic material. The energy bound into the second component causes liquefaction of the thermoplastic material at the interface between the second component and the vibrating tool, and the force clamping the second component between the vibrating tool and the opposing member causes the liquefied thermoplastic material to become liquefied. From between the second component and the vibrating tool and into the structure of the first component.

In the variant of Fig. 4, in contrast, the first component 1 does not need to be loaded by the directed pressure at all. Rather, liquefaction will occur at one or both of the end faces 2.1, 2.2 and at the interface/interfaces between the tool 3 and the opposite member 4, respectively. In the configuration of FIG. 4 the roles of the tool 3 and the opposite member 4 can be reversed, i.e., in a sub variant, the member reaching through the second component 2 and having a distal foot will function as the opposite member. Can, while the tubular member in contact with the proximal end surface of the second component can be coupled with the vibration source and can function as a sonotrode.

5 shows a configuration comparable to that of FIG. 4. The tool comprises a distal foot portion (3.2) having a shaft portion (3.1) and an outcoupling surface (3.3), wherein liquefaction is performed by the outcoupling surface and the second component. It occurs at the first interface between the incoupling surfaces 2.1. The proximal end face 2.2 of the second component 2 is pressed against a second interface with the distal end face 4. 1 of the opposite member 4 during processing. During the process, this second interface may be maintained or may be moved distal or proximal.

At the liquefaction interface (first interface) the entire cross section of the second component is liquefied. For example, for the outer diameter of the tool (at least in the region of the liquefaction interface, thus in the posterior configurations), the outer diameter of the foot (3.2) approximately corresponds to the inner diameter of the initial opening (1.1) (e.g., equal or maximum) May be selected to be smaller than 10% or up to 5% or up to 3%) and/or may be selected to be (approximately) equal to or greater than the outer diameter of the second component (e.g., corresponding to or Or larger, or smaller by up to 7%, up to 4%, or up to 2%). In particular, liquefaction is performed so that when the tool 3 is removed, the part of the second component that has not been liquefied at the liquefaction interface(s) does not remain on the object or the part of the second component that has not been bonded thereto does not remain on the object. Can be.

Thus, the configuration of FIG. 5 is an embodiment of the configuration where the penetration leads to reinforcement and/or lining of the first component by the material of the second component. In particular, the reinforcement and/or lining may relate to the walls of the opening of the first component.

A wide variety of approaches for reinforcing and/or lining components with thermoplastics are described in international application PCT/CH2013/000102 by the same applicant as the present invention, which is incorporated herein in its entirety by reference.

All the embodiments shown in FIGS. 3 to 5 are embodiments suitable for configurations in which the force which ultimately causes the hydrostatic pressure is combined into the tool 3 which transfers energy as a tensile force (traction force).

6 is a modified example in which the energy used for penetration is not mechanical energy but radiant energy. For this purpose, the tool 3 is provided as a light guide. Radiant energy can be absorbed, for example, at the proximal end face 2.1 of the second component inside the second component 2, or if the second component is sufficiently transparent, the foot of the opposite member 4 It can be absorbed at the interface to (4.2).

In the variant of FIG. 7, the second component 2 is made of a non-thermoplastic material (or a material that can be liquefied at a temperature higher than the melting temperature of a solid having thermoplastic properties) and has a plurality of openings 25. And a sheath element 24 and a thermoplastic member 23 inserted into or insertable into the sheath member. During the process, energy is combined into the thermoplastic member until the material of the thermoplastic member is liquefied and pressed out of the opening 25. In Fig. 7, an optional reinforcing layer 51 is also shown that is subjected to mechanical loads occurring during pressing.

As for the embodiment of FIGS. 1A-1D, for all configurations of FIGS. 2-7, the irreversible transition will occur after penetration and resolidification by the thermoplastic material or in some cases concurrently with it.

Figure 8a shows a first component bonded to a second component 2 according to the prior art approach. It is assumed that the first and second components have different densities and different physical properties. For example, the second component may have come into contact with the surface of the first component in a liquid state and then cooled (cast). Due to the relatively abrupt transition at the cavity interface, the physical quantity Q will change as a function of position in a stepwise manner as shown in Fig. 8B. Thus, the derivative of this function with respect to position will contain very high peaks at the interface. Thus, quantities such as temperature-change-induced stress (or, for example, where the physical quantity Q is the coefficient of thermal expansion) can tend to be very large at the interface and thus have a detrimental effect. Similar considerations apply to other sensitive quantities.

If instead the approach according to the invention is chosen, there will be a significant penetration zone 11 as shown in Fig. 9a. Thus, the average value of both Qs can change more continuously (Fig. 9B), and thus phenomena such as stress at the interface are significantly reduced.

10 shows a solar or energy collection installation. The central body 101 comprises porous graphite and is therefore an excellent heat absorber. A plurality of mounting and heat conducting members 102 are fixed to the central body. The members each comprise a heat conducting core (the core may comprise a passive heat conductor or means for guiding a fluid) and a carbonized, initially thermoplastic material penetrating the central body 101. The facility also includes a plurality of solar re-directors 104 (actively tilted mirrors) that direct incident sunlight 105 onto a central body. Reference numeral 103 denotes a device for directing the collected heat to a utilization stage comprising, for example, a turbine for producing electricity with a generator.

The flow chart shown in FIG. 11 shows the manufacture of a ceramic foam (foam) having reinforced and/or lined openings by a process as described herein. For example, a ceramic foam can be the body of a fuel cell that needs to be electrically contacted from or to which charge has to be transported and thus electrical, or may be a ceramic foam for any other application, e.g. the previously discussed application. I can.

While the first component made of ceramic foam is still a molded body prior to firing/sintering of the molded body, the process lining/reinforcing the initial opening by causing penetration of the thermoplastic material, for example, as shown in FIG. Includes that. For example, the molded body can be molded directly into the initial opening (casting, etc.), after which the opening is lined and/or reinforced. In embodiments of the present invention, since no pressure is applied to the object except for a small pressure of the liquid penetrating into the pores during liquefaction, small dimensional stability of the molded body is sufficient for this purpose.

After the infiltration step, the green body is fired and/or sintered. For this reason, the penetration material of the second component must be selected to sustain the temperature during this process. In the illustrated embodiment, the second component material is selected to be a ceramic material that is itself thermoplastic prior to curing. Then, in the firing/sintering process, the second component material is sintered to the ceramic material at the same time as well.

After the firing/sintering process, reinforcing/lining can be used to bond another member (joining member/electrical contact, thermal conductor, etc.) to the ceramic body.

Claims (22)

As a method of manufacturing a heterogeneous composite, the method comprises the following steps:
-Providing a first component and a second component,
ㅇ The first component is porous or can generate pores if it is under hydrostatic pressure,
ㅇ The second component contains a solid with thermoplastic properties,
-Positioning the second component relative to the first component and coupling energy into the second component causing at least portions of the second component to liquefy and penetrate into the pores of the first component or other structure Whereby the first component is penetrated by the material of the second component, creating a composite comprising a first component, a second component and a penetration zone between the first component and the second component. The step of doing; And,
-Causing at least an irreversible transition of the second component to produce a modified composite material.
Includes,
The method of manufacturing a heterogeneous composite, characterized in that the irreversible transition comprises a chemical reaction occurring within the second component or between the first and second components. The method of claim 1,
A method of manufacturing a heterogeneous composite, characterized in that the irreversible transition is caused by energy input to the composite. The method of claim 2,
Energy input is a method of manufacturing a heterogeneous composite, characterized in that it includes heat treatment of the composite. The method according to any one of claims 1 to 3,
Wherein the irreversible transition comprises diffusion of a material of a first component to a second component and/or diffusion of a material of a second component to a first component. The method according to any one of claims 1 to 3,
A method for manufacturing a heterogeneous composite, characterized in that by the same process causing an irreversible transition of the second component, an irreversible transition of the first component is also caused. The method according to any one of claims 1 to 3,
The first component comprises a molded body, the method comprising firing the molded body after the infiltrating step. The method of claim 6,
A method of manufacturing a heterogeneous composite, characterized in that the irreversible transition is caused by the step of firing. The method according to any one of claims 1 to 3,
Coupling energy into the second component comprises coupling mechanical vibrations into the second component. The method of claim 8,
During the step of coupling energy into the second component, the second component is clamped between the vibrating tool and the opposing member, wherein the opposing member is different from the first component. The method of claim 9,
The energy bound into the second component causes the liquefaction of the thermoplastic material at the interface between the second component and the vibrating tool, and the force clamping the second component between the vibrating tool and the opposing member causes the liquefied thermoplastic material to occur. A method of manufacturing a heterogeneous composite material, characterized in that causing a movement between the second component and the vibrating tool into the structure of the first component. The method of claim 9,
Further comprising the step of removing the vibrating tool, characterized in that the part of the second component that has not been liquefied after the removing step does not remain on the object, or that part of the second component that has not been bonded thereto does not remain on the object. Method for manufacturing heterogeneous composites. The method of claim 8,
The method of manufacturing a heterogeneous composite, characterized in that the vibrations are coupled into the second component by means of a tool on which a tensile force acts during the joining step. The method according to any one of claims 1 to 3,
The second component comprises a core of a non-thermoplastic material or a core of a material capable of being liquefied at a temperature higher than the melting temperature of a solid having thermoplastic properties. The method according to any one of claims 1 to 3,
A method for producing a heterogeneous composite, characterized in that the solid having thermoplastic properties comprises a matrix of a thermoplastic polymer and a metallic filler. The method according to any one of claims 1 to 3,
A method for producing a heterogeneous composite, characterized in that the solid having thermoplastic properties comprises a matrix of a thermoplastic polymer and a ceramic filler. The method of claim 15,
Ceramic filler is a method of manufacturing a heterogeneous composite, characterized in that the green body (green body). The method of claim 15,
The method of manufacturing a heterogeneous composite, characterized in that the ceramic filler is fired. The method according to any one of claims 1 to 3,
The method of manufacturing a heterogeneous composite, characterized in that the first component comprises a ceramic. The method according to any one of claims 1 to 3,
The first component is a method of manufacturing a heterogeneous composite, characterized in that it comprises a metallic foam (foam). The method according to any one of claims 1 to 3,
The first component is a method of manufacturing a heterogeneous composite, characterized in that it comprises a graphite foam (foam). The method according to any one of claims 1 to 3,
The method of manufacturing a dissimilar composite, characterized in that the step of causing the first component to be penetrated by the material of the second component is carried out until the penetration zone has a depth of at least 1 mm. delete

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